The Main Stand at Maine Road was always quiet except on rare occasions. It was where the expensive seats were. Now we have four main stands.
The other thing is, back in the day, a group of you could decide to go on Friday night, or even Saturday morning, and just turn up on the day. Now everything has to be planned weeks or even months in advance. The spontaneity is gone. And that's before you get onto ticket prices that only the comfortably-off (or richer) can really afford. It's only a matter of time before some matches are designated as "black-tie only" affairs.